The most famous example of media alteration is when time magazine altered OJ Simpson's photograph. I have included a link http://blogcritics.org/archives/2005/08/31/012306.php to an article about it.
It creates an ethical problem because it is flirting with truth when you alter information. this is coming from the consumer point of view. The ethical standards should serve the consumer.
I personally feel like altering any type of information or lying to get information is unethical